TRANSACTIONS OF THE SECTIONS. 
15 
cores. The cores being placed in suitable helices, could be so excited that the con- 
1 -uous poles were of the same or of opposite names. A bar of bismuth was freely 
impended, so that both poles could act upon it simultaneously. When the cores 
ucre excited, so that the poles were alike, the bismuth was repelled; when the poles 
•<r uf different names, the bismuth bar remained motionless; all action upon it 
*. nmiulled. This experiment coufircns those of Reich, and proves that the con- 
> n, whatever it may be, which is evoked by one magnetic pole is neutralized by 
V other, that each particular pole evokes a condition peculiar to itself; and here 
' obtain the first glimpse of the dual nature of the force under consideration. The 
vt prirtion of the inquiry treated of the deportment of diamagnetic bodies when 
*rtid upon, first, by the magnet alone; secondly, by the electric current alone; 
x®! thirdly, by the current and the magnet combined. When wc speak of the de- 
,• "ticent of bismuth in any one of the coses mentioned, no exact meaning can be 
•''ii i.i il to the phrase unless it be first strictly defined in what direction, as to the 
l ,,UK ■ "f crystallization, the mass has been cut. A har of bismuth, in which the 
■' i Unw “t principal cleavage are parallel to the length of the bar, and acted upon by 
niaguct alone, will set itself perpendicular to the magnetic lines of force. A 
" d»* contrary, in which the planes of cleavage are transverse, will set itself 
I 1 d!H to the solid lines. Thu former bar Professor Tyndall calls a normal dia- 
"uii in; bar; the latter an abnormal one. The most perfect antithesis is observed 
1 ' *■ <nses between the deportment of the normal diamagnetic bar and a bar of soft 
!!' ’ lae hirers which cause a deflection of the former from right to left produce a 
, Knium l®tter from left to right. If the former take up a position of equili- 
'!!° lmtn south- west to north-east, the position taken by the latter will be from 
•; r *° nortl, - w ^t; and throughout the whole experiments the same oppo- 
■ C 1 ! 8 * 1 ? ' 9 ® x ^*bilcd. By mechanical means, an abnormal magnetic bar was 
i al l 8 i f vvllich sot lt5 length nt right angles to the line joining the poles. 
"j' ,nal diamagnetic bar shows throughout a deportment precisely antithetical 
the ibnorml v° rnia ' m . u S net| c one; hut when wc compare the normal magnetic with 
!>,. j,.. . a diamagnetic, or the normal diamagnetic with the abnormal magnetic, 
■ 'hence of , 15 ln al1 cases Perfectly alike. It is evident, therefore, that unless the 
1 1 "O' n ;*l a T re , bc fttten ‘lvd to, the greatest errors aud the most inaccurate con- 
'3 U.r loacnpH 6 nj 011 l * u ‘ deportment both of magnetic and diamagnetic bodies 
• "n|itir,n u,u: i )Ut tb c thing which chiefly concerns us here is the strong pre- 
' >«•! in mnlh .• i CXIieriracnt8 justify, that whatever be the nature of the influence 
’ Ul influence rEv'®* 111 actioa of currents, of magnets, or of both combined ; 
’ i,r tnient of V 1 le 8arae natur ®> but antithetical in its manner of distribution, the 
' c|earerT agI ] et J 0 bodies is to be referred. The next section of the inquiry 
pUtvfi that th 10 “ to the nature of diamagnetic action. Two helices were 
iron cores which fitted into thorn were about 
' .' 1 ‘ touched ,i *” Cc , tlt,f llJ centre; the helices were at opposite sides of the plane 
' 111 't a bismutV k s r °/.tl‘ e cores. A helix of copper wire was introduced, and 
' 8tt »pendcd r 1 * un B iU, d four-tenths of an inch in diameter was 
' ’ f A current h • thu ends of the bar "era opposite to those of the soft iron 
[ 11 ■' the current If g Stnt throu Sh the helix, if the bismuth bar within it wereex- 
lf If in the Wa8 P r °babla that the nature of the excitcmeut would mani- 
rc pelledbv tb T mwed ,n a certain direction, the ends of the diamagnetic 
r ' :v crscd, the “ eeIectr ‘>-magnets; when the current flowing through the helix 
, ''tained when ? Ue . C, ' da ' ve|, c at traded by the magnets. The same effect 
f i Was reversed "n" of rcv . e *‘sing the helix current, the polarity of the two 
! t ‘ I *t they were n r c ” a, P arln g the deflections with those of soft iron, it was 
• I, ,‘; ‘i r " n bar to Eu ctly , antithetical. The excitement which caused the ends 
' l a. ^cite ment caused the ends of the bismuth bar to be repelled, 
ct,. " Jll >uth bar to } , cai,sed the ends of the iron bar to be repelled caused those 
l °j.“ wb ftt p.ll ,i r;i ^ t , ed . ^11 these experiments point irresistibly to the 
f'.'icc |, e .' ‘^dilution opr*!! • ,d V al tHSgnetic distribution in iron may be. aprecisely 
Nw for Ce but ft, 1,1 " l8mu th,—or, in other words, that the diamagnetic 
bat the polarity is the reverse of magnetic polarity. If, 
